The invention generally relates to the field of an X-ray machine, and in particular relates to a linkage mechanism of a scattered ray inhibition apparatus and a radiation field control apparatus, a collimator, and an X-ray machine.
In the field of the X-ray machine, a radiation field control apparatus exists in a collimator for limiting the X-ray Field of View (FOV) of X-rays emitted from a tube, and it is generally composed of two rectangular blades that are oppositely disposed. As is well-known, there is a certain distance between the tube and the collimator, thus a part of the X-rays emitted from the tube will be scattered from the distance, which also may be called off-focal radiation. For a general X-ray machine, the amount of the off-focal radiation thereof normally approaches 15% of the amount of the focal radiation. In addition to the primary X-ray beams, the part of off-focal radiation also will radiate on a patient, which thus increases X-ray dosage to the patient and also affects the quality of imaging, and also makes faint images of the anatomical structures outside the field of interest.
Therefore, in order to solve the problem, a scattered ray inhibition apparatus is generally disposed over the distance between the tube and the collimator for inhibiting the X-rays emitted from the tube from being scattered from the distance. The scattered ray inhibition apparatus usually employs a fixed blade disposed in a plane which is as close as possible to the exit of the tube, or a fixed cone. For an X-ray machine, the tube emits cone-shaped X-ray beams, when the FOV changes, the scattered ray inhibition apparatus remains unchanged, thus, in the case of a small FOV, the quality of imaging is rather undesirable. Hence, the scattered ray inhibition apparatus needs to be in linkage with the radiation field control apparatus.
At present, at least some known X-ray machines have had the function of linking the scattered ray inhibition apparatus with the radiation field control apparatus. However, they generally have a wheel disc and a shift lever mounted between the scattered ray inhibition apparatus and the radiation field control Apparatus. One end of the shift lever is connected to the radiation field control apparatus while the other end thereof is connected to one end of the wheel disc, and the other end of the wheel disc is connected to one end of the blade (the scattered ray inhibition apparatus). Thus, as the radiation field control apparatus changes, the shift lever drives the wheel disc, the wheel disc further drives the blade, causing the blade to swing. Hence, the inhibition effect in such manner is undesirable and the structure is comparatively complicated. Since the tube of the X-ray machine emits cone-shaped radiation beams, if the blade or the cone is able to translate with the motion of the radiation field control apparatus, the achieved inhibition effect is then ideal.
U.S. Pat. No. 4,246,288 also discloses a method of linking a scattered ray inhibition apparatus with a radiation field control apparatus, but the method is complicated in structure.